A Letter in Answer to Another of Mr. Hen. Oldenburgh's, Wherein he Desired an Explanation of a Paragraph, Touching the Use of the Intestinum Caecum, Publisht in the Philosoh. Tranfact. Num. 95 Anno 1673

CMVRRIVS CFARNIENSIS FOROIVLIMO DESTVSMIL LEGIIADPF IVLISECUNDI ANXXVSTIP FORTVNAE CONSERVA TRICI L.SENECIA NIVSMAR TIVS.LEG VI VICT A Letter in answer to another of Mr. Hen. Oldenburgh's, wherein he desired an Explanation of a Paragraph, touching the use of the Intestinum Caecum, publish'd in the Philoloh. Transact. Num. 95 anno 1673. where Paragraph is this. The use of the Intestinum Caecum, subservient to that of the Colon and Rectum; manifest in such Animals, where Nature intends a certain and determinate Figure to the Excrements. Sir, I did not think of Explaining my Sense of the use of the Caecum until I had had the leisure and opportunity of purposely examining the Intestines of most kinds of Animals. But because I am much mistaken by the Person, who as you tell me, is desirous to be anonymous to me, him I mean who raised the Scruples you sent me, upon the second Paragraph, which says the use of the Intestinum Caecum to be subservient, &c. I shall be forc'd to tell you, what I presume may prove as near the truth, as any one of the many Conjectures extant in Authors, about the unknown use of this Part. I understand by determinate Figure. 1. The Excrements divided into many small parts of a like shape, such as Sheep, Deer, Conies, Hares, Rats, Mice, Horses, Caterpillers, some Snails, &c. do naturally void. 2 In a greater latitude, I oppose figured Excrements to liquid, as C. Celsus in some place doth: Thus the Dung of Pigeons, Geese, and Men, Cats, Dogs, &c. may be said to be figured. Now the Caecum in my Opinion is subservient in some measure to the figuration of both, but most manifest in the first kind. My meaning is, that probably the use of the Caecum is to keep the Excrements, which shall pass into its Cavity (and I believe all, or most part of them do so in found Animals) so long, until they are sufficiently drained, baked, hard'ned, or of a due consistence (as Clay is tempered for the mould) to receive the Figure to be given it from the Colon and Rectum. This use I say of the Caecum, seems to me to be much more manifest in such Animals, as have figured Excrements of the first kind. In Rats for example, whose Excrements are constantly alike figured, the Caecum is very large, more capacious than the Stomach itself. But its use in receiving the Excrements or exhausted Chyle, is not more apparent, from its large Capacity, than that other of farther drawing and tempering them to a stiffness, for the service of the Colon, from the admirable contrivance. trivance and structure of this latter Gut, which is a Phenome non that deserves further Consideration: it is I say to be noted, that immediately under the valve of that Gut, in this Animal, are certain spiral Fibers, which make a kind of screw: now it seems to me, that the Excrements, after they are brought to a due Consistency by the necessary stay they make in the Caecum, and being carried out thence into the spiral foldings, or screw of the Colon, cannot descend in a perpendicular, as formerly through the small Guts, but still gently glide, and that very leisurely by the winding of the screw; whence arises the Figure. And I am apt to believe, that if the Caecum of a Rat, or any of the first kind of Animals mentioned, was tyed up, or otherwise hindred from its receipt, the Animals would unavoidably fall into a Diarrhoea: there being I say no reason, that I can foresee, why the yet liquid Excrements or exhausted Chyle, such as we constantly find it, even at the very bottom of the small Gut, should stop at the entrance of the Colon, and not speedily glide through the screw, in a downright descent, that is, elude the devise of Nature, and make the configuration of that so curiously contrived part useless; we, I say, supposing the experiment to have taken away the necessary Diverticulum and Repository of the unprepared Excrements, in tying up the Caecum. I know not whether the Observation will hold good in general Terms, because I say I have not yet purposely examined divers Animals in Nature, viz. That where ever there are elegantly figured Excrements of the first kind, there is ever a capacious Caecum; and on the contrary the less accurately figured and more liquid the Excrements of any Animals are, the lesser the Caecum, or none at all. This is certainly true, that some Animals, which are naturally loose, have no Caecum at all, or very little as the Talpa, the Echinus terrestis, the Gulo, and amongst Birds the Wood-pecker kind, the Hawke kind, &c. We shall not trouble you at present with our observations concerning Figure of Excrements in the divers Species of Animals already by us examined; nor of the place of their being so figured. Also we shall pass by at present our thoughts of the manner of the Caecum's reception, and preparing the Excrements for the Colon. We likewise forbear to offer some doubts we have, concerning Natures end, in the necessary Figuration of the Excrements crements in some Animals, as first to prevent Diarrhoea's; secondly to abide Hunger the better; Thus snails in the Winter rest with full Intestines: Thirdly and chiefly to heighten the fermentation and digestion, (of which I shall shortly publish my thoughts in another Tract) in the Stomach and Small Guts. Also in like manner, why to some Animals liquidity of Excrements is as necessary. What we have hastily writ at present, being only intended, for the better understanding that Paragraph, and not all, that this Subject would incite me to say, &c. Thus far have I sent you of that Letter; the remainder I will shew you, when I shall see you here. Westminster, Nov. 6. 1683. SIR, Your most humble Servant, M. Lyster. The learned Author of the preceding Discourse visiting the Bath the last Summer, Anno 1683, exactly designed the Roman Inscriptions prefixed to this Tract, according to the Originals now to be seen at Bath in Somersetshire, formerly published in Camden, and since by Guidot, which he did to shew how unlike the Originals are, to the Letters of the Press; and that therefore to represent them well and faithfully, they ought first to be carefully designed and then Engraved. Which is here faithfully done. The Letters of Fig. 2, 3, 4, are graven larger than the rest, because they are five Inches complete. Fig. the 8th contains the Inscription of an Altar found near the Roman Camp, which is placed within the Angle, where the two Rivers, Medloe and Erwim meet, a little mile South-west of Manchester in Lancashire, and preserved in the Garden of the worshipfull Edward Moseley de Holme Armiger, where the same worthy Person saw it, and read it.